Within a high-temperature region of a gas turbine engine, components are exposed to harsh operating conditions and high-temperatures (e.g., about 1000 C). As a result, these parts may have shorter lifetimes and require more frequent inspections than other parts of the turbine engine. In particular, wear damage caused by excessive relative motion at the interface between loosely loaded parts is one common failure mechanism of gas turbine high-temperature section parts. Combustion parts are more prone to wear damage due to a higher level of vibration motion from the harsh operating environment. Typically, to inspect for wear occurring at the interface between two parts requires the gas turbine to be taken offline. Once the gas turbine is offline, visual inspection of the parts occurs as well as physical measurement of the surfaces to determine how much wear has occurred.
Proximity sensors have been used in some instances to measure displacement between two surfaces that are separated by a finite distance. As the displacement between the two surfaces changes, the proximity sensor can detect this change and report information representative of the relative distance between the two parts. Such a proximity sensor, however, is not useful for wear measurement as the two parts that are wearing are doing so because they are touching rather than being separated by some distance.
Thus, there remains a need for a wear sensor that can operate in the high-temperature section of a gas turbine engine and perform real-time condition monitoring without requiring the gas turbine engine to be offline.